In recent years it has become apparent that the neuotransmitter serotonin (5-hydroxytryptamine i.e. 5-HT) is associated with a number of physiological phenomena such as acid secretion, anxiety, depression, sexual dysfunction, emesis, memory, hypertension, appetite, and sleep. [Glennon, R. A., J. Med. Chem., 30, 1 (1987)]. Multiple receptors have been found for 5-HT. These receptors have been classified as 5-HT, 5-HT.sub.1, 5-HT.sub.2, and 5-HT.sub.3 receptors with the former being further classified as 5-HT.sub.1A, 5-HT.sub.1B, 5-HT.sub.1C and 5-HT.sub.1D. The binding activity of a compound to one or more of these 5-HT receptors has been recognized as being predictive of physiological activity of the compound.
Flaugh in U.S. Pat. No. 4,576,959 (issued 1986) disclosed a family of 6-substituted-4-dialkylamino-1,3,4,5-tetrahydrobenz[cd]indoles which show binding affinity for 5-HT receptors and are described as central serotonin agonists. Leander in U.S. Pat. No. 4,745,126 (1988) disclosed a method for treating anxiety in humans employing a 4-substituted, 1,3,4,5-tetrahydrobenz[cd]indole-6-carboxamide derivative.
Certain indolines have been reported, as in U.S. Pat. No. 4,110,339 of Bach et al. (1978), Flaugh et al., J. Med. Chem., 31, pp 1746-1753 (1988), Flaugh in U.S. Pat. No. 4,576,959 and European Patent Application 0153083 (published 1985). These were used as intermediates in the preparation of the corresponding indoles.
It has now been found that certain 4- and 6-substituted hexahydrobenz[cd]indoles (indolines) particularly certain stereoisomers of such indolines are useful in treating conditions requiring alteration of the 5-HT.sub.1.sbsb.A receptor function in the body. The 2aS, 4R isomer has been found to be particularly useful.